scholarly journals ESD Reviews: Evidence of multiple inconsistencies between representations of terrestrial and marine ecosystems in Earth System Models

2020 ◽  
Author(s):  
Félix Pellerin ◽  
Philipp Porada ◽  
Inga Hense
Keyword(s):  
Marine Ecosystem ◽  
Marine Ecosystems ◽  
Climate System ◽  
Biological Processes ◽  
Earth System ◽  
Climate Feedbacks ◽  
Ecosystem Models ◽  
System Models ◽  
Marine Ecosystem Models ◽  
Earth System Models

Abstract. Terrestrial and marine ecosystems interact with other Earth system components through different biosphere-climate feedbacks that are very similar among ecosystem types. Despite these similarities, terrestrial and marine systems are often treated relatively separately in Earth System Models (ESM). In these ESM, the ecosystems are represented by a set of biological processes that are able to influence the climate system by affecting the chemical and physical properties of the environment. While most of the climate-relevant processes are shared between ecosystem types, model representations of terrestrial and marine ecosystems often differ. This raises the question whether inconsistencies between terrestrial and marine ecosystem models exist and potentially skew our perception of the relative influence of each ecosystem on climate. Here we compared the terrestrial and marine modules of 17 Earth System Models in order to identify inconsistencies between the two ecosystem types. We sorted out the biological processes included in ESM regarding their influence on climate into three types of biosphere-climate feedbacks (i.e. the biogeochemical pumps, the biogeophysical mechanisms and the gas and particle shuttles), and critically compare their representation in the different ecosystem modules. Overall, we found multiple evidences of unjustified differences in process representations between terrestrial and marine ecosystem models within ESM. These inconsistencies may lead to wrong predictions about the role of biosphere in the climate system. We believe that the present comparison can be used by the Earth system modeling community to increase consistency between ecosystem models. We further call for the development of a common framework allowing the uniform representation of climate-relevant processes in ecosystem modules of ESM.

Towards a new trait-based framework bringing together terrestrial and marine ecosystems in Earth system models.

2020 ◽  
Author(s):  
Felix Pellerin ◽  
Philipp Porada ◽  
Inga Hense
Keyword(s):  
Critical Evaluation ◽  
Marine Ecosystems ◽  
Climate Dynamics ◽  
Biological Traits ◽  
Biological Processes ◽  
Earth System ◽  
System Models ◽  
Earth System Models ◽  
Global Influence ◽  
Multiple Interactions

<p>The climate on Earth arises from multiple interactions between the different spheres, including the biosphere. Within the biosphere, the organisms composing the various types of ecosystem are characterized by a set of traits involved in biological processes that can influence the climate system. Identifying and integrating these traits into models such as earth system models (ESM) is thus crucial to predict the future of earth climate. While an important number of biological processes are similar, the amount and the type of traits considered to represent these processes can vary considerably among ecosystem types in current ESMs. Such inconsistencies could bias our perception of the global influence of biosphere on climate dynamics. Here we first list the biological traits that have been included in the terrestrial and oceanic modules of the CMIP5 Earth system models. By comparing the traits and associated processes, we reveal consistencies and inconsistencies in trait representation among both ecosystem types. Based on a critical evaluation we propose a new conceptual framework that allows to describe the climate relevant traits in a consistent way in terrestrial and oceanic modules of ESMs. This framework can also be used to identify new traits characterizing terrestrial and/or marine ecosystems, and to integrate them in ESMs.</p>

scholarly journals Ensemble projections of global ocean animal biomass with climate change

2018 ◽  
Author(s):  
Heike K. Lotze ◽  
Derek P. Tittensor ◽  
Andrea Bryndum-Buchholz ◽  
Tyler D. Eddy ◽  
William W. L. Cheung ◽  
...  
Keyword(s):  
Climate Change ◽  
Marine Ecosystem ◽  
Marine Species ◽  
Global Ocean ◽  
Earth System ◽  
System Models ◽  
Climate Change Effects ◽  
Marine Ecosystem Models ◽  
Earth System Models ◽  
Ensemble Projections

AbstractClimate change is shifting the abundance and distribution of marine species with consequences for ecosystem functioning, seafood supply, management and conservation. Several approaches for future projection exist but these have never been compared systematically to assess their variability. We conducted standardized ensemble projections including 6 global fisheries and marine ecosystem models, forced with 2 Earth-system models and 4 emission scenarios in a fished and unfished ocean, to derive average trends and associated uncertainties. Without fishing, mean global animal biomass decreased by 5% (±4%) under low and 17% (±11%) under high emissions by 2100, primarily driven by increasing temperature and decreasing primary production. These climate-change effects were slightly weaker for larger animals and in a fished ocean. Considerable regional variation ranged from strong biomass increases in high latitudes to strong decreases in mid-low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to differences among ecosystem or Earth-system models were similar, suggesting equal need for model improvement. Our ensemble projections provide the most comprehensive outlook on potential climate-driven ecological changes in the ocean to date. Realized future trends will largely depend on how fisheries and management adapt to these changes in a changing climate.

scholarly journals Observing carbon cycle–climate feedbacks from space

2018 ◽  
Vol 115 (31) ◽  
pp. 7860-7868 ◽  
Author(s):  
Piers J. Sellers ◽  
David S. Schimel ◽  
Berrien Moore ◽  
Junjie Liu ◽  
Annmarie Eldering
Keyword(s):  
Carbon Dioxide ◽  
Earth System ◽  
Climate Feedbacks ◽  
System Models ◽  
Component Processes ◽  
The Impact ◽  
Atmospheric Concentrations ◽  
Earth System Models

The impact of human emissions of carbon dioxide and methane on climate is an accepted central concern for current society. It is increasingly evident that atmospheric concentrations of carbon dioxide and methane are not simply a function of emissions but that there are myriad feedbacks forced by changes in climate that affect atmospheric concentrations. If these feedbacks change with changing climate, which is likely, then the effect of the human enterprise on climate will change. Quantifying, understanding, and articulating the feedbacks within the carbon–climate system at the process level are crucial if we are to employ Earth system models to inform effective mitigation regimes that would lead to a stable climate. Recent advances using space-based, more highly resolved measurements of carbon exchange and its component processes—photosynthesis, respiration, and biomass burning—suggest that remote sensing can add key spatial and process resolution to the existing in situ systems needed to provide enhanced understanding and advancements in Earth system models. Information about emissions and feedbacks from a long-term carbon–climate observing system is essential to better stewardship of the planet.

scholarly journals Carbon–Concentration and Carbon–Climate Feedbacks in CMIP5 Earth System Models

2013 ◽  
Vol 26 (15) ◽  
pp. 5289-5314 ◽  
Author(s):  
Vivek K. Arora ◽  
George J. Boer ◽  
Pierre Friedlingstein ◽  
Michael Eby ◽  
Chris D. Jones ◽  
...  
Keyword(s):  
Carbon Concentration ◽  
Coupled Model ◽  
Co2 Flux ◽  
Co2 Concentration ◽  
Climate System ◽  
Climate Feedback ◽  
Earth System ◽  
System Models ◽  
Common Framework ◽  
Earth System Models

Abstract The magnitude and evolution of parameters that characterize feedbacks in the coupled carbon–climate system are compared across nine Earth system models (ESMs). The analysis is based on results from biogeochemically, radiatively, and fully coupled simulations in which CO2 increases at a rate of 1% yr−1. These simulations are part of phase 5 of the Coupled Model Intercomparison Project (CMIP5). The CO2 fluxes between the atmosphere and underlying land and ocean respond to changes in atmospheric CO2 concentration and to changes in temperature and other climate variables. The carbon–concentration and carbon–climate feedback parameters characterize the response of the CO2 flux between the atmosphere and the underlying surface to these changes. Feedback parameters are calculated using two different approaches. The two approaches are equivalent and either may be used to calculate the contribution of the feedback terms to diagnosed cumulative emissions. The contribution of carbon–concentration feedback to diagnosed cumulative emissions that are consistent with the 1% increasing CO2 concentration scenario is about 4.5 times larger than the carbon–climate feedback. Differences in the modeled responses of the carbon budget to changes in CO2 and temperature are seen to be 3–4 times larger for the land components compared to the ocean components of participating models. The feedback parameters depend on the state of the system as well the forcing scenario but nevertheless provide insight into the behavior of the coupled carbon–climate system and a useful common framework for comparing models.

scholarly journals Earth system models of intermediate complexity: closing the gap in the spectrum of climate system models

2002 ◽  
Vol 18 (7) ◽  
pp. 579-586 ◽  
Author(s):  
Claussen M. ◽  
Mysak L. ◽  
Weaver A. ◽  
Crucifix M. ◽  
Fichefet T. ◽  
...  
Keyword(s):  
Climate System ◽  
Earth System ◽  
System Models ◽  
Intermediate Complexity ◽  
Closing The Gap ◽  
Earth System Models ◽  
Climate System Models

scholarly journals Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change

2019 ◽  
Vol 116 (26) ◽  
pp. 12907-12912 ◽  
Author(s):  
Heike K. Lotze ◽  
Derek P. Tittensor ◽  
Andrea Bryndum-Buchholz ◽  
Tyler D. Eddy ◽  
William W. L. Cheung ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Impacts ◽  
Marine Ecosystem ◽  
Model Development ◽  
Trophic Levels ◽  
Global Ocean ◽  
Earth System ◽  
System Models ◽  
Earth System Models ◽  
Ensemble Projections

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.

Controls of the TCRE in Earth system models

2021 ◽  
Author(s):  
Ric Williams ◽  
Paulo Ceppi ◽  
Anna Katavouta
Keyword(s):  
Radiative Forcing ◽  
Thermal Response ◽  
Earth System ◽  
Climate Feedbacks ◽  
Ocean Heat Uptake ◽  
Surface Warming ◽  
System Models ◽  
Heat Uptake ◽  
Ocean Carbon ◽  
Earth System Models

<p>The controls of a climate metric, the Transient Climate Response to cumulative carbon Emissions (TCRE), are assessed using a suite of Earth system models, 9 CMIP6 and 7 CMIP5, following an annual 1% rise in atmospheric CO2 over 140 years. The TCRE is interpreted in terms of a product of three dependences: (i) a thermal response involving the surface warming dependence on radiative forcing (including the effects of physical climate feedbacks and planetary heat uptake), (ii) a radiative response involving the radiative forcing dependence on changes in atmospheric carbon and (iii) a carbon response involving the airborne fraction (involving terrestrial and ocean carbon uptake). The near constancy of the TCRE is found to result primarily from a compensation between two factors: (i) the thermal response strengthens  in time from more surface warming per radiative forcing due to a strengthening in surface warming from short-wave cloud feedbacks and a declining effectiveness of ocean heat uptake, while  (ii) the radiative response weakens in time due to a saturation in the radiative forcing with increasing atmospheric carbon. This near constancy of the TCRE at least in complex Earth system models appears to be rather fortuitous given the competing effects of physical climate feedbacks, saturation in radiative forcing, changes in ocean heat uptake and changes in terrestrial and ocean carbon uptake.</p><p>Intermodel differences in the TCRE are mainly controlled by the thermal response, which arise through large differences in physical climate feedbacks that are only partly compensated by smaller differences in ocean heat uptake. The other contributions to the TCRE from the radiative and carbon responses are of comparable importance to the contribution from the thermal response on timescales of 50 years and longer for our subset of CMIP5 models, and 100 years and longer for our subset of CMIP6 models.</p><p> </p>

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